- Coal has been a dependable source of power for energy supply for several countries in the world. Coal power plants work similarly to nuclear power plants, hydroelectric power plants and geothermal plants. While the power of atomic fission, water and earth's heat are the fuel used respectively in the later plants, coal power plants burn coal to generate steam that drive the power turbine. As the turbine rotates, the system of electromagnet and copper wires generate electrical charges that could be stepped up by a transformer and sent across transmission lines to end users.

Coal probably accounts for close to 60-70% of the historical and current World Power plants. Most countries have invested several billions of dollars to acquire the infrastructure, the technology and train the personnel for mining and processing electricity from coal over years. Decommissioning the coal power plants will not be an easy sell to such countries. Secondly there are still large deposits of coal unused worldwide. 

Disadvantages of Coal as fuel for Power Plants

• Coal fired plants release greenhouse gases (GHGs), e.g. CO2 to the atmosphere as coal is burnt. The GHGs (particularly CO2) have been shown to be responsible for fast changing climate resulting in global warning and its several effects and problems. Burning coal also releases other pollutants (e.g. Sulphur Dioxide (SO2); Nitrogen Oxides (NOx), particulates (e.g. mercury) etc) to the atmosphere. thus contributing to global warming and having some other negative impacts on the environment.
• Coal is a fossil fuel. It is non-renewable. We will eventually run out of coal supply. It is pertinent to look for alternative sources such as solar, wind, nuclear, geothermal, biomass etc. to make our coal deposit and leave some reserves for coming generations.

Clean Coal Technologies

Some people are proposing Clean Coal Technologies (CCTs), to ensure that we keep our old friendly coal plants and still ensure that our environment is not negatively impacted. Clean Coal technologies are technologies aimed at reducing the environmental impacts from the use of coal for energy.

A cleaner production of energy from coal will be favoured by most nations simply because the infrastructures are already in place and all that may be required are upgrades to add the cleaning components. This could avoid the very high costs of investing in brand new technologies and decommissioning the coal plants.

Some of the CCTs proposed are:

• Chemically washing minerals and impurities of coal prior to burning for energy;
• Gasification - converting carbonaceous materials, such as coal, petroleum, or biomass, into carbon monoxide and hydrogen by reacting the raw material at high temperatures with a controlled amount of oxygen and/or steam, resulting in a gas mixture called synthesis gas or syngas, which itself is a fuel.
• Treating the flue gas (smoke) from the coal stove/furnace with steam to remove sulfur dioxide;
• Carbon Capture and Storage (CCS) systems that could capture the carbon dioxide from the flue gas and store it up underground permanently preventing its release to the atmosphere.

Obviously all the technologies above may have to be employed in a single processing cycle.

The development of the CCTs mentioned above (particularly the CCS) is still in an early stage. Demonstration plants are being proposed everywhere to explore CCS and other CCTs.

Other Information Sources

• Carbon Capture and Storage - Wikipedia
• CO2 sequestration - Wikipedia
• Clean Coal Technology on Wikipedia
• Clean Coal - America's Power
• Clean Coal Technologies Inc.
• Clean Coal Technologies - World Nuclear Association